Lévothyrox : side effects reported by thousands of patients

Health 18 August, 2017


Published the 17.08.2017 at 19: 08


Keywords :

thyroïdemédicamenteffets side

The new generation of Lévothyrox causes the anger of patients. Last march, this medication is indicated in disorders of the thyroid gland has changed, and formula. “In order to ensure a stability more important to the content of active substance levothyroxine throughout the shelf-life of the drug, Merck conducted, at the request of the state Agency of medicines (MSNA), a modification of the formula of Levothyrox “, indicated the health care agency at the time.

But patients are now complaining of adverse effects since the change of formula – intense fatigue, headache, weight gain, constipation, dizziness… A petition has been launched and has collected 20 000 signatures and 9000 comments and testimonials. It calls for the provision of the two formulas on the market.


In march, the MAN assured him that “the bioequivalence between the old and the new formula” had been proven, but she advised that, despite everything, some patients to perform an assay of TSH [blood assay of thyroid stimulating hormone] six to eight weeks after the beginning of the making of the new formula, ” as a precaution “.

The agency called for these new assays in several cases : if ” your balance therapy has been particularly difficult to achieve, you have thyroid cancer, you have a cardiovascular disease (heart failure or coronary artery and/or rhythm abnormalities), the patient is a child, an elderly person or pregnant “.

Dosages HRT

“If you have any questions or if you experience any unusual symptoms that may translate to an imbalance of the thyroid, do not hesitate to contact your doctor or pharmacist,” it said again the MAN.

“Too many patients cannot tolerate the new Lévothyrox, they experience significant side effects. When we know that it is very difficult to stabilize the TSH, it is not acceptable to have changed this drug, ” write the authors of an online petition, requesting to the concerned laboratories to return to the old formula.